Refrigerating plant



Oct. 13, 1936. E. KGI

REFRIGERATING PLANT Filed Nov. 23, 1933 Patented Oct. 13, 1936 UNITED STATES PATENT OFFICE REFBIGEBATING PLANT Emil Kgl, Winterthur. Switzerland, assignor to the iirm Sulzer Frres Socit Anonyme, Winterthur, Switzerland Claims.

'Ihis invention relates to refrigerating plants of the kind including a compressor, evaporator and condenser. y

Refrigerating plants are sometimes started 5 and stopped by opening and closing a valve for regulating the cooling water supply to the condenser, means such frexample as an auxiliary electrical circuit being closed at the same time as the valve is actuated, so that the compressor is started. When automatic operation is employed the cooling water regulating valve is sometimes actuated by a thermostat or pressostat. In arrangements of this type, however, if when the regulating valve has been opened, the supply of cooling water wholly or partly i'ails due, for example, to wrong manipulation or trouble in the water supply system, the pressure within the condenser will rise to such a high value that if a pressostat is employed the condenser pressure may be equal to or above the maximum pressure within the range of the pressostat, with the result that the motor driving the compressor will be stopped.

The transmission of heat to the surrounding air which takes place even when the supply of cooling water to the condenser has ceased tends to result in intermittent starting and stopping of the compressor and such intermittent 'operation is liable to cause injurious eects on the compressor without being accompanied by any appreciable cold production. If, with a view to preventing such intermittent operation, the pressostat is made non-reversible so that restarting the compressor has to be effected by hand, a stoppage in the case of a. plant which is not continually supervised may continue even when the cooling water supply to the condenser has been resumed, with consequent risk of damage to goods which have to be cooled. The present invention has for its object to overcome the above diiliculties.

To this end according to the present invention the machine for driving the compressor is controlled in accordance with the difference between the pressure at/two points in the cooling water circuit of the condenser, whereby the compressor is operated when such pressure difference exists,

or is stopped when such pressure difference ceases to exist, but the compressor cannot be started when such pressure diilerence does not exist.

Conveniently the machine for driving the compressor is controlled by a diierentially operated regulating device actuated in accordance with the diierence between the pressures at two points in the cooling circuit oi' the condenser. The diilerentially operated regulating device may be connected directly across the cooling water circuit with same unaltered or it may be connected to the cooling circuit of the condenser 5 with one of the two points of connection being a Venturi throat arranged in the cooling circuit, and the other point being as before, i. e. a point of unrestricted cross-section.

'Ihe differentially operated regulating device 10 may comprise two expansible chambers separated by an intermediate wall or plate with one chamber communicating with the condenser cooling circuit at a point adjacent to the high hydrostatic pressure or inlet part, whilst the 15 other chamber communicates with the cooling circuit at a p oint nearerto the outlet or low hydrostatic pressure part, an adjustable. loading spring acting on the intermediate wall in-opposition to the pressure within that chamber 20 which communicates with the high pressure part of the circuit. y

In the accompanying drawing, Fig. 1 illustrates a construction according to the invention diagrammatically and by way of example.

Fig. 2 shows a modification in which a Venturi throat is inserted in the cooling medium circuit.

In the construction shown in Fig. l, a motor I drives a compressor 2 which draws refrigerant from a suction pipe 3 and delivers it, after com- 30 pression, through a delivery pipe 4 to a condenser 5. 'I'he refrigerant passes from the condenser 5 through a pipe 6 to the evaporator 34'. For cooling'the refrigerant, cooling medium is supplied to the condenser 5 through a feed pipe 35 1, the cooling medium after passing' through the condenser being discharged or returned to the cooling medium circuit through a discharge pipe 8.

The plant derives power from electric -mains through a main switch 9, and a cut-out I0 is provided for automatically switching the motor I in and out of operation, the power supply to the motor being controlled as hereinafter described by two pressostats II and I2, a thermostat I3, and a diilerentially operated regulating device Il adapted to control a tilting switch I5. The pressostat Il operates in -accordance with the pressure in the suction pipe 3 whilst the 50 pressostat I2 operates in accordance with the pressure in the delivery pipe 4. The switch IS is' associated with a signal lamp I6 and a trip coil I'l for operating the cut-out I0, a valve I8 operated by a solenoid I9 being provided for con- 55 hmmm #Mmmm mmmmmmmmm m M mmm mm @www mm mmmmm-wmmmmmmw @Mmmm mmrmmmmw www mmmmmwmmm mmmmmmmmm al ,M Mmmunmmm rm .mmm m mmmudmmm nmmmmmewr. ....mmmmP @www Mmmm.. @Wmme mdmhmmmmmm.;mwwmm mmmwwmwmmmmmwHmmm@mmmwmmm e.d.s.m. u a. n tao t. t Mmwmmm .mln um Mmmmwmwwwmmwm mmmmmwmmmmmmmmmmmmmm .www

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diierentially operated regulatinh l"device by which the motor for driving the compressor may be controlled in accordance with the diilerence between the pressures at two points in cooling medium circuit of the condenser.

3. In a refrigerating plant aspeiaimed in claim 2, the use ot a differentially operated regulating device connected across the cooling medium circuit of the condenser.

4. In a refrigerating plant as claimed in claim' s 'fit a'point adjacent to the high hydrostatic pressure or inlet part whilst the other chamber communicates with that cooling circuit at a point nearerl tothe outlet or low hydrostatic pressure 'an adjustable loading spring acting on the interxfiediste wall in opposition to the pressure within that chamber which communicates with the high pressure part of the circuit.

5. In a refrigerating plant as claimed in claim 2, the use of a din'erentially operated regulating device connected to a Venturi throat which is arranged in the cooling medium circuit of the condenser and also to said circuit at a point vof rela.- tively unrestricted cross section thereof.

man. Klier. 

